pdfviewer: when q start, and an operator is called, it should not be able to see operands before q. nest/unnest are similar with pop/push - simulates a stack of stacks, in a single stack

Review URL: https://codereview.chromium.org/23033022

git-svn-id: http://skia.googlecode.com/svn/trunk@10873 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/PdfViewer/SkPdfFont.h b/experimental/PdfViewer/SkPdfFont.h
index 09e01ac..51e0329 100644
--- a/experimental/PdfViewer/SkPdfFont.h
+++ b/experimental/PdfViewer/SkPdfFont.h
@@ -211,7 +211,7 @@
     };
 
     inline unsigned int ToUnicode(unsigned int ch) const {
-        if (fToUnicode) {
+        if (fToUnicode && fToUnicode->fCMapEncoding) {
             return fToUnicode->fCMapEncoding[ch];
         } else {
             return ch;